| 1. |
- Tuskan, Gerald A., et al.
(författare)
-
The obscure events contributing to the evolution of an incipient sex chromosome in Populus : a retrospective working hypothesis
- 2012
-
Ingår i: Tree Genetics & Genomes. - : Springer Science and Business Media LLC. - 1614-2942 .- 1614-2950. ; 8:3, s. 559-571
-
Forskningsöversikt (refereegranskat)abstract
- Genetic determination of gender is a fundamental developmental and evolutionary process in plants. Although it appears that dioecy in Populus is genetically controlled, the precise gender-determining systems remain unclear. The recently released second draft assembly and annotated gene set of the Populus genome provided an opportunity to revisit this topic. We hypothesized that over evolutionary time, selective pressure has reformed the genome structure and gene composition in the peritelomeric region of the chromosome XIX, which has resulted in a distinctive genome structure and cluster of genes contributing to gender determination in Populus trichocarpa. Multiple lines of evidence support this working hypothesis. First, the peritelomeric region of the chromosome XIX contains significantly fewer single nucleotide polymorphisms than the rest of Populus genome and has a distinct evolutionary history. Second, the peritelomeric end of chromosome XIX contains the largest cluster of the nucleotide-binding site-leucine-rich repeat (NBS-LRR) class of disease resistance genes in the entire Populus genome. Third, there is a high occurrence of small microRNAs on chromosome XIX, which is coincident to the region containing the putative gender-determining locus and the major cluster of NBS-LRR genes. Further, by analyzing the metabolomic profiles of floral bud in male and female Populus trees using a gas chromatography-mass spectrometry, we found that there are gender-specific accumulations of phenolic glycosides. Taken together, these findings led to the hypothesis that resistance to and regulation of a floral pathogen and gender determination coevolved, and that these events triggered the emergence of a nascent sex chromosome. Further studies of chromosome XIX will provide new insights into the genetic control of gender determination in Populus.
|
|
| 2. |
- Zhang, Guojie, et al.
(författare)
-
Comparative genomics reveals insights into avian genome evolution and adaptation
- 2014
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 346:6215, s. 1311-1320
-
Tidskriftsartikel (refereegranskat)abstract
- Birds are the most species-rich class of tetrapod vertebrates and have wide relevance across many research fields. We explored bird macroevolution using full genomes from 48 avian species representing all major extant clades. The avian genome is principally characterized by its constrained size, which predominantly arose because of lineage-specific erosion of repetitive elements, large segmental deletions, and gene loss. Avian genomes furthermore show a remarkably high degree of evolutionary stasis at the levels of nucleotide sequence, gene synteny, and chromosomal structure. Despite this pattern of conservation, we detected many non-neutral evolutionary changes in protein-coding genes and noncoding regions. These analyses reveal that pan-avian genomic diversity covaries with adaptations to different lifestyles and convergent evolution of traits.
|
|
